TY - CHAP
T1 - Runx2 regulation during development and regeneration of bone in the zebrafish (Danio rerio)
AU - van der Meulen, T.
AU - Schipper, H.
AU - Samallo, J.
AU - Kranenbarg, S.
AU - van Leeuwen, J.L.
AU - Franssen, H.G.J.M.
PY - 2004
Y1 - 2004
N2 - A key feature of vertebrates is the development of bone.
In mammals the gene Runx2 is considered a major
switch in bone development, as knockout mice for
Runx2 never develop any bone. We cloned two zebrafish
Runx2 homologues, Runx2a and Runx2b, and
assessed their roles in zebrafish. The homologues are
80% identical, but they are both more than 80% identical
to Runx2 in other species and Runx2a is 10% more identical
to tetrapod Runx2 than Runx2b is. We wanted to
find out whether the sequence diversification of the
zebrafish homologues led to function diversification.
Two promoters control the expression of Runx2. Each
promoter results in a different messenger start. We
assessed promoter activity by performing real time quantitative
PCR. For both genes, one of the promoters is
much more active than the other and between genes the
promotor activity is different. During development both
genes are expressed simultaneously in developing bony
structures in the head. In the pectoral fin however,
Runx2a is expressed in the fin bud and Runx2b in elements
at the base of the fin. The adult pectoral fin and
its bony elements can regenerate after injury. During this
process, induced by fin-clipping, Runx2b expression
was found in the fin itself. From this we conclude that
the two Runx2 homologues in zebrafish are both active
in bone development and regeneration, but have
acquired slightly different functions. In addition we find
that development and regeneration are not regulated by
identical pathways.
AB - A key feature of vertebrates is the development of bone.
In mammals the gene Runx2 is considered a major
switch in bone development, as knockout mice for
Runx2 never develop any bone. We cloned two zebrafish
Runx2 homologues, Runx2a and Runx2b, and
assessed their roles in zebrafish. The homologues are
80% identical, but they are both more than 80% identical
to Runx2 in other species and Runx2a is 10% more identical
to tetrapod Runx2 than Runx2b is. We wanted to
find out whether the sequence diversification of the
zebrafish homologues led to function diversification.
Two promoters control the expression of Runx2. Each
promoter results in a different messenger start. We
assessed promoter activity by performing real time quantitative
PCR. For both genes, one of the promoters is
much more active than the other and between genes the
promotor activity is different. During development both
genes are expressed simultaneously in developing bony
structures in the head. In the pectoral fin however,
Runx2a is expressed in the fin bud and Runx2b in elements
at the base of the fin. The adult pectoral fin and
its bony elements can regenerate after injury. During this
process, induced by fin-clipping, Runx2b expression
was found in the fin itself. From this we conclude that
the two Runx2 homologues in zebrafish are both active
in bone development and regeneration, but have
acquired slightly different functions. In addition we find
that development and regeneration are not regulated by
identical pathways.
M3 - Abstract
VL - 137A
T3 - Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
SP - S62-S63
BT - Abstracts of the Annual Main Meeting of the Society for Experimental Biology
T2 - Annual Main Meeting of the Society for Experimental Biology,Edinburgh, UK
Y2 - 29 March 2004 through 2 April 2004
ER -